Atlas assembled plant by plant

Natural History Museum volunteers catalog county's flora

By Mike Lee, staff writer
| 2 a.m.Dec. 24, 2008

Volunteer Olive Ball worked on the plant atlas at the San Diego Museum of Natural History. Since 2002, an army of several hundred trained volunteers has collected most of the 37,000 samples. (Laura Embry / Union-Tribune)

Volunteer Olive Ball worked on the plant atlas at the San Diego Museum of Natural History. Since 2002, an army of several hundred trained volunteers has collected most of the 37,000 samples. (Laura Embry / Union-Tribune)

BALBOA PARK 
On the top floor of San Diego's Natural History Museum, well out of public view, the region's largest collection of plant specimens is growing like a weed.

Nearly 9,000 samples were added this year alone – a museum record – thanks to a mostly volunteer project called the San Diego County Plant Atlas. The effort, which began in 2002, is an ambitious plan to round up and catalog every type of plant from every corner of the county.

That will allow researchers to analyze the region's floral diversity and chart changes, including those linked to global warming. It also should give regulators a better sense about plant species when considering development proposals.

Despite its successes, the project's future is uncertain. Like so many nonprofit enterprises, its funding sources are shrinking. With no grant money coming in, the museum is picking up the tab of roughly $150,000 a year for the atlas, said Jon Rebman, the museum's curator of botany.

He said the help won't last indefinitely. “We are worried about the future of the project,” Rebman said. “If the ball drops, it just won't be picked up.”

Rebman proposed the plant atlas about seven years ago as a companion to the museum's authoritative tome, the San Diego County Bird Atlas, which was published in book form in 2004. At the start, Rebman said he was appalled at how little scientific information was available about a county with the most diverse flora in the nation.

“Basically, I said we don't know much about our land and we are losing huge chunks of it to development,” he said.

At least by one measure, he was right. Atlas research has turned up more than 250 species or subspecies that had not previously been recorded in the county.

With support from The San Diego Foundation, and later the National Science Foundation and others, Rebman adapted bird atlas methods for use with plants. A map used for both efforts divides the county into about 480 squares of three miles each.

While the bird atlas includes roughly 500 species, the plant atlas targets approximately 2,500 species countywide. Rebman doesn't accept observational reports. He wants samples, or “vouchers,” of each kind of plant found, along with data about the elevation, geographic coordinates and other details.

That way, researchers of the future will have tangible proof of what grew here in the early 2000s, rather than having to rely on photos or written descriptions.

Rebman figures it may take another decade to reach his goal of roughly 100,000 specimens. Many will be duplicates, a strategy devised partly to show subtle differences in plants that appear the same to untrained eyes.

Since 2002, an army of several hundred trained volunteers has collected most of the 37,000 samples, which another team of volunteers painstakingly arrange on oversized sheets of archival-quality paper.

“I consider this therapy,” said Jan Domnitz of La Mesa, who regularly donates her time to display leaves and flowers on pages. She handles the delicate specimens with tweezers and pallet knives as she glues them down for posterity.

“The whole point is for a scientist to come in and see all aspects of the plant,” she said.

Scientists aren't the only ones who can see the work done by Domnitz and her friends. Digital images of the specimens, along with an interactive plant-mapping program, are in an online archive on the museum's Web site.

“It's a body of raw data that could be used in many different ways in the future that we haven't even imagined yet,” Rebman said.

Thomas Oberbauer, a habitat official for the county, is among the atlas project's biggest fans. “This kind of information is important for us to determine what we need to protect, where we need to protect things and how things might change in the future because it sets a baseline,” he said.

Plant atlas director Mary Ann Hawke already is using the fast-growing archive to research changes in bloom periods. She's curious whether samples collected over the past century show that climate change is altering flowering times. She doesn't know the answer yet.

“For me, the collection is interesting, but it's just a way to generate data about what the plants are doing and the most important question of all: What are they telling us about how we are changing our world?” she said.